Panchang & Muhurta

What a panchang actually is

A panchang is a calendar that describes the quality of time rather than merely counting it. Where a Gregorian date says which day it is, a panchang says what kind of day it is — and that judgement comes from five components, the five angas the word names.

All five are derived from one thing: the angular relationship between the Sun and the Moon, plus the Moon’s position against the fixed stars. Nothing else is needed, which is why the panchang can be computed for any date and any place.

The five limbs

• Tithi — a lunar day, the time the Moon takes to gain 12° on the Sun. Thirty of them make a lunar month, split into the waxing Shukla paksha and the waning Krishna paksha. Their length varies between roughly 19 and 26 hours.
• Vara — the weekday, and the one limb that behaves like ordinary time. In the Hindu reckoning a vara runs sunrise to sunrise, not midnight to midnight.
• Nakshatra — the Moon’s lunar mansion, one of 27 divisions of 13°20′ each. More is read from the Moon’s nakshatra than from any other single fact in the almanac.
• Yoga — the sum of the solar and lunar longitudes, divided into 27 named spans. Not to be confused with the planetary yogas of chart analysis; the word is shared, the meaning is not.
• Karana — half a tithi, so two per tithi and eleven names in rotation.

Why the same day differs between almanacs

Two panchangs can disagree about the same date, and it is usually one of three reasons rather than an error:

Sunrise evaluation. The limbs are reported for the moment of local sunrise. A tithi that ends at 09:15 is still “today’s tithi” in the almanac even though it is gone by mid-morning, and a city an hour to the west may report a different one entirely.

Amanta or purnimanta. The lunar month can be taken to end at the new moon (amanta, common in the south and west) or at the full moon (purnimanta, common in the north). The tithis are identical; the month names differ by one for half of each month.

Ayanamsha. Sidereal calculation needs a value for the precession offset, and different traditions use slightly different ones.

Choosing an hour, not just a day

The muhurat tables sit on top of the five limbs and subdivide the day:

• Choghadiya splits daylight and night into eight parts each, labelled Amrit, Shubh, Labh, Char, Udveg, Kaal and Rog;
• Hora gives each hour a planetary ruler in the classical Chaldean order;
• Gowri Panchangam, Do Ghati and Panchaka Rahita are further regional slot systems;
• Abhijit Muhurat is the short auspicious window around local noon;
• Rahu Kaal, Gulika and Yamaganda are the daily inauspicious windows;
• Chandrabalam and Tarabalam judge the day against your birth rashi and nakshatra rather than against everyone’s.

Every one of these is computed from local sunrise and sunset, so all of them move with the city and with the season. A muhurat table copied from another city’s almanac is simply the wrong table.